"Salinity is a particular issue in the prime wheat-growing areas of Australia, the world's second-largest wheat exporter after the United States," says Gilliham. "Salt-tolerant crops will be an important tool to ensure future food security."

For over a decade researchers have been working on developing salt-tolerant durum wheat (Triticum turgidum) - the favoured wheat for making pasta, bulgur and couscous.

Farmers can get a hefty premium for the wheat but it is a lot more salt-sensitive than bread wheat (Triticum aestivum).

In this latest research, Gilliham and colleagues identified the gene, called TmHKT1;5-A, responsible for the salt tolerance trait.

The gene codes for a kind of salt pump that stops salt being transferred into the leaves, where it can be toxic to the plant.

"Salty soils are a major problem because if sodium starts to build up in the leaves it will affect important processes such as photosynthesis, which is critical to the plant's success," says Gilliham.

"The salt-tolerant gene works by excluding sodium from the leaves. It produces a protein that removes the sodium from the cells lining the xylem, which are the 'pipes' plants use to move water from their roots to their leaves."

Gilliham and team found that the presence of the gene boosted yields in saline fields by 25 per cent.

Also, because the salt pump doesn't 'cost' the plant much, there is no drop in yield in low-saline fields, says Gilliham.

He says the next step is to develop bread wheat with the salt-tolerant gene.

As 69 per cent of Australia's wheat belt is affected by salinity, the development will help boost productivity in these saline areas, says Gilliham.

He says it is also possible the technology could be used to grow crops in irrigated areas affected by salinity.

Gilliham says GM technology could be used to transfer the gene into other crops as well.

Plant breeding expert, Professor Richard Trethowan of University of Sydney describes the research as a "significant development". Trethowan says the findings will be particularly exciting if they can be transferred into bread wheat.

Ecologist Professor Paul Adam from University of New South Wales describes the work as "elegant", but says it may encourage people to grow crops in areas that are not already being exploited for agriculture, with possible impacts on biodiversity.